Yeah, that's interesting: A Sigma lens costing more than the Nikon equivalent.
Looking at the MTF curves of the Sigma
The theoretical curves seems to hold quite well. In fact they look even better than with the Nikon! But there is a very pronounced contrast drop-off in the FX-area.

I had an inquiry today with regard to the new AF-S version vs. the old AF one:

Quote:

I'm looking for a 50mm lens for my Nikon D80. I'm torn between the new and the old version of the Nikkor 50mm/1,4. That why I enjoyed your review and review diary.

But basically, what would you recommend taking in mind that the 1,4D is approximatly 120EUR cheaper than the new 1,4G.

I can autofocus with the 1,4D while D80 has a build-in motor, right? both are usable on FX models right? (eventually we will all upgrade to full frame)

Yes, you're right: both lenses are FX-capable and both work on your D80/90 etc.
What made me switch from the AF to the AF-S version was some unrliability I encountered with the older version in auto-focussing. My lens could sometimes be really off on my D80. Not so much that I immediately recogized it when looking through the viewfinder but when reviewing the image on my computer I had to consider the shot a loss.
I assume that this resulted from some type of aberration that this lens had and which fooled the AF-system of the D80 into thinking that the image was perfectly in focus. It did only happen a few times but I became reluctant to trust the lens.
With the new AF-S on my D300 I had some cases where the focus settled totally off, but in this case you could easily see it in the viewfinder and you could give it a second try. When the AF-system found focus the focus-quality is very good.

So all in all it is not easy to give a recoomendation here, because the cases of bad focussed images on the old lens were not often. So you have to decide how much the additional peace of mind together with faster focussing and some better IQ is worth the higher price.

Plus the difference that the 50mm is a FF/FX lens and the 35mm is a DX lens.
You can read photozones analysis of the 35mm here and of the 50mm there.
In comparison the 50mm has less distortion, less vignetting and less CA, whereas the 35mm seems a tad sharper in the center up to f/4.0 (all compared on DX format).

I've finally had time to update my usual testshots of this lens to make it even easier to compare to my newer reviews. I've also thrown in as a goody the (near) corner performance on a D700!
So here we go:

Investigating on the loCA of the new Nikon AF-S 85/1.4G I did a series of test-shots to
(1) give you a comparison of loCA across different apertures and
(2) make the comparison across different large aperture Nikon primes namely the 35/1.4G, the 50/1.4G and the 85/1.4G

So here's the result for the AF-S 50/1.4G showing a crop at below 50%:
Clicking through the image gives you access the 100% crop. Processing was done in CaptureNX2 with standard setting meaning lateral CA removal was ON, loCA removal=OFF. At f/5.6 the greenish (background) and reddish (foreground) hues are almost gone - but not completely.

The second image gives you the results from switching loCA remocal ON at 100% (again, you see the crop here at <50%):
This works pretty good! Bear in mind though that CaptureNX 2's secret sauce for loCA removal seems to depend on the magnification and gets better the smaller the magnification is (this test-shot was at 1:20). That can be confirmed from real-life shots.

Q: "Hi just read ur review on the Nikkor AF_S 50 mm.I've got a Nikon D60 and want a Lens to do portrait and event photography. do u think its a good choice for such purpose?

I appreciate ur reply.thanx"

A: I think it's perfect for both situations, as it works like a short tele on a DX-body. But you might reconsider this choice if your subjects are normally further away from you - street photography might be such a situation where you need more reach, or if you're not close enough to the stage of an event. Then a 85mm could be more appropriate.
On the other hand: If you're part of the crowd at an event the 50mm could even be too narrow and a 35mm or even shorter prime could prove useful.
Best thing to do is analyze some situations where you have used your current equipment (probably one of the standard-zooms) and see which focal lengths you used. You can normally get this information from the EXIF-data of your images.